Extending EV Battery Lifespan Through Partial Direct Liquid Cooling: A Novel Thermal Management Strategy

Abstract

This study presents an experimental assessment of how thermal management strategies influence the degradation kinetics of lithium-ion battery modules. To enhance temperature control at the system level, a novel partial Direct Liquid Cooling (DLC) configuration was developed, establishing direct physical contact between the cell surfaces and a dielectric fluid. The efficacy of the proposed DLC design in mitigating battery aging was validated through a rigorous comparative analysis against conventional Indirect Liquid Cooling (ILC), the current benchmark technology in electric vehicles. The experimental data demonstrate that the proposed partial DLC strategy significantly enhances the battery system’s thermal control, maintaining it within the optimal temperature range under identical electrothermal stress. Apart from providing higher thermal management control than conventional strategies, linear extrapolation of the measured capacity-fade trends indicates a projected increase in battery durability of 67.4%, highlighting the potential of the proposed partial DLC strategy to substantially extend system lifespan and withstand extreme operating conditions. Furthermore, while the ILC subsystem exhibited severe degradation with a 24% increase in internal resistance, the proposed partial DLC system remained remarkably resilient, retaining a stable resistance profile. These findings validate the technical viability of the proposed partial direct liquid cooling strategy as a high-performance thermal management solution for e-mobility applications.